Decided to try an Xicoy 2 position retract valve in a new, non jet, warbird. It works great except it leaks badly in the gear down position. I've programmed it per the directions but it still leaks. Have I missed something or do I just have a bad valve?

The hissing sound comes from the valve but the leak is on your air cylinders somewhere.
Use pliers to cut air flow from retract cylinders one at the time and when hissing stops you have found the leaky one. I have had similar problems and my culprit was UP door cylinder and once in my skymaster f-15 had a leaky retract cylinder.

Ceeray is probably correct but I have had a leaky Xicoy valve. The valve actually consists of an aluminium sub plate and two subminiature pneumatic solenoid valves each held onto the sub plate by two very small Phillips head screws. These screwheads are under the silver foil wrapping over the top of the valves. I prodded with a screwdriver to find the heads and tightened them and bingo the leak stopped.

worth a try once you’ve eliminated the cylinders and piping as the source of the leak.

Malcolm

I have had the same problem when I first started to use this valve. I was replacing a BVM retract and brake valve during a refurb on my Viper. The system was working perfect with the BVM valve, so I thought. So I sent Xicoy into DreamWorks, and they replaced it under warranty. The second valve arrived and I was having the same issues. I thought I got another bad valve. Because assuming the new valve wasn't working again, since with the BVM valve everything worked. I then started to seriously looking into my air system. Come to find out that I had 3 leaks in my system that were harder then H3ll to find. One of the hardest to find was on a retract nipple that was safety wired too. At some time when I had replace the air lines on previous maintenance, I did a no-no and used an Xacto knife to cut the previous air hose off. The knife scored the nipple. With the hose safety wired, there was still a micro leak. This leak was enough to make me think the valve wasn't working properly, when in reality, it was my system. I am telling you this, because I would have bet money on my air system being tight. Just because it worked with the BVM valve. The Xicoy valve is sooooooo sensitive that any micro leak will cause it to not properly work. So, triple check EVERY connection with soapy water. Just because it is safety wired, doesn't mean that it won't leak. The valve has worked flawless since I found all of my leaks.........that I would have bet money on weren't there. The hiss you hear is the valve releasing the pressure so that there isn't a vapor lock to move the cylinders in the opposite direction. I just bought 2 more of these valves for my next jet. Good Luck!

Thanks for all of the great info guys!
I traced all my lines and was unable to find a leak anywhere other than the valve.
I pulled the covering foil back and checked the screws but it still leaks like a sieve.
Sending it back to Chief for a new one on Monday.
Thanks again!

Bugger, bad luck. I was sure it was the cylinders leaking. I once had something stuck into Xicoy valve's pressure release hole and it finally caused my retracts stopping in midway due pressure on both sides. It was replaced..

It is hard sometimes to isolate the problem ...

CatBoater I wish you luck! But, if you get the second valve and you are still having issues.......it isn't the valve. As Ceeray said that it could be an internal leakage of the cylinder O-rings. Since the valve releases the pressure on the "opposite" side of the pressure, an internal cylinder leak is more difficult to find. Especially if you have one of the Chinese brands or even Robart, because their precession isn't as close as the higher end jet retracts. Good Luck!